This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. This study occurs in two phases: Phase I, GCRC GH/IGF-1 Evaluation. The basis of this Phase I study is to identify those children who are growth hormone deficient. The neuropsychological status of children GHD and GH normal will be compared for differences in their clinical profiles. Children found to be Growth Hormone normal will be re-evaluated after 1 year. If they are found again to be GH normal, then they will have completed their role and will be discharged from the study. Those children who are Growth Hormone Deficient will be re-examined in six months. If at that time they remain deficient they will be offered Phase II. Children found to be Growth hormone abnormal will be re-evaluated after 6 months. If they are found to be normal they will be re-evaluated in 1 year. If that evaluation reveals that they are GH normal, then they will exit the study. If the evaluation reveals that they are GHD, they will be invited to enter Phase II. Phase II is a one-year trial on Growth Hormone therapy. During the Phase II year, the children are seen at decreasing intervals of frequency to monitor their response to GH replacement. They will be monitored for therapeutic effects (growth, development and cognitive changes) as well as side effects. Subjects will receive injections (shots) of GH replacement therapy (GHRT) daily for one year. These injections are the current standard of care for children with GHD. For the first three months subjects will see the doctors monthly and have weekly telephone calls to check for side effects and answer any questions. For months 4-12, subjects will see the doctors on months 6, 9, and 12 for checkup and monitoring. Also, subjects will have monthly phone calls to check for side effects. The children are followed through our acquired brain injury clinic at Kluge Children's Rehabilitation Center. At the end of one year, the study therapy will be discontinued, those subjects who continue to need therapy will be referred as necessary, and the results of the study will be shared with parents and participants.